Survival after repair of congenital diaphragmatic hernia (CDH) is limited by adequacy of prenatal pulmonary development. Ventilatory function may be compromised further by multiple adverse perinatal factors that necessitate intermittent pressure ventilation (IPPV). Barotrauma frequently complicates IPPV, and is observed in several forms. These complications lead to ventilatory and hemodynamic dysfunctions. Of 50 infants with CDH repaired in the first 24 hr of life, 36% survived. Infants operated in the first 8 hr had a lower survival rate (28%) than those operated between 8 and 24 hr (50%). Tension extrapulmonary air (TEPA) was observed in 30 infants (60%), was significantly higher in dying infants (p<0.03), and was associated with IPPV in 29 cases. All infants had a prophylactic ipsilateral chest tube, and 12 had a prophylactic contralateral tube. A contralateral tube was used therapeutically in 21 infants. Malfunction of prophylactic or therapeutic tubes occurred in 16 infants of whom 4 survived. Ipsilateral small (<50%) lung size observed at operation with inability to inflate the lung appeared to increase the incidence of TEPA and mortality. Survival of 5 infants with small ipsilateral lung size and the death of 8 infants with lung size sufficient to fill half or more of the hemithorax indicated the occurence of adverse factors other than lung hypoplasia. One or more prenatal abnormalities and/or postnatal complications in 37 infants, were significantly more frequent among dying infants than survivors (p<0.01), and were associated with increased use and higher pressure of IPPV, and higher incidence of TEPA and mortality. At autopsy of 23 infants there was gross evidence of PIE and/or TEPA in 9; histologic sections revealed pronounced pulmonary perivascular air dissection and compression in 13 infants, more pronounced in the contralateral lung. Of several potential mechanisms causing pulmonary hypertension in CDH, the role of pulmonary interstitial perivascular air pressure, "air block" has been supported in animal experiments and in this and other clinical studies. Compression by persistent perivascular air appears to amplify the pulmonary vasoconstrictive effect of hypoxemia and acidemia, and limits the response of pulmonary hypertension to pharmacologic agents. From this study we conclude: (1) In CDH, the primary pathology and associated adverse perinatal factors frequently require ventilatory support. (2) Ventilatory support in CDH is associated with a high incidence of barotrauma and a significantly related mortality. (3) PIE and TEPA are probable active participants in the pathogenesis of pulmonary hypertension and cardiopulmonary failure. (4) Reduction of the risks of barotrauma requires effective prophylactic and therapeutic management of PIE and TEPA.
- Congenital diaphragmatic hernia (CDH)
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health